The raw material to make paper

1. The introduction of wood as a source of papermaking fibers at the end of the 19th century was a great development which changed the future course of the pulp and paper industry and paved the way for the mass production of paper on modern high-speed paper-machines. The abundance and relatively low cost of wood compared to materials before used for papermaking, opened up new markets and laid the basis for the modern pulp and paper industry.

2. Now wood is the principal raw material for pulp. Pulp is the raw material from which paper, paper-board, some plastics and many other products are made.

3. All wood is made of the same basic parts: cellulose, fibers, lignin (a glue-like substance), which holds those fibers together, sugars, resins, mineral salts, and other substances. Wood fibers are very thin. They are thinner than a human hair. The fiber length of hardwoods ranges from 1 to 2 millimetres and that of softwoods ranges from 3 to 6 millimetres.

4. The task of the papermaker is to separate the fibers and to rearrange them in new patterns and in new combination with other substances for making different products. This may be done by several methods: mechanical, chemical, semichemical, and thermomechanical. The method chosen depends upon the type of wood used and the requirements of the end-product.

5. Historically softwoods have been preferred to hardwoods, owing to their greater fiber length. Since supplies of softwoods have been adequate for pulp demands up to the present time, the main task of the pulp industry was to improve the pulping of softwoods. This resulted in a high level of technology in softwood pulping.

6. The recent shortage of softwoods has made it necessary to use more hardwoods. Today they are in all pulping processes.

II Прочтите 2-ой абзац текста и письменно ответьте на следующий вопрос:

What products are made from pulp?

[1] kauri – каури (вечнозеленое хвойное дерево)

[2] Polynesian – полинезиец; полинезийский

[3] tuatara – туатара или гаттерия (древнейшее наземное позвоночное животное)

[4] governor-general – генерал-губернатор

[5] House of Representatives – Палата представителей

Дата добавления: 2015-07-11